The Importance of Wave Transience and Dissipation

What is lacking in this picture is the mechanism for deceleration of the zonal winds provided by the Eliassen-Palm divergence or any other dissipation force (Leovy, 1964 Schoeberl and Strobel, 1978 Holton and Wehrbein, 1980). Assuming that wave transience and dissipation can be neglected in the thermodynamic (but not the zonal momentum) equation, and considering the dominant terms in the momentum equation (3.67), we can write 

This expression describes the so-called downward control principle (Haynes et al., 1991). It shows that in the extratropics (f 7 0), the vertical velocity w (and hence the vertical transport) at a given 

An accurate representation of wave drag is essential for chemical modeling because chemical species are advected by the mean meridional circulation and are also transported by the irreversible mixing which accompanies wave drag. Modeling studies (e.g., Schoeberl and Strobel, 1978 Holton and Wehrbein, 1980) sometimes use a Rayleigh coefficient to crudely parameterize the effects of wave dissipation. In this case, a deceleration is assumed to act linearly on u, and is substituted for the wave drag term Gu as follows  

Two effects must be considered At altitudes sufficiently high for the collisions between ions and neutral particles to become infrequent, and 

The second effect to be considered is the deflection of the weakly charged air flow by the electromagnetic field through the Lorentz force. The corresponding drag coefficients are (Hong and Lindzen, 1976) 

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